The present invention relates to an automatic seatbelt retractor for a seatbelt system in a motor vehicle.
Automatic seatbelt retractors return a seatbelt automatically back to its"" original position after use. An automatic seatbelt retractor should prevent catching in the otherwise slack seatbelt located inside a vehicle when getting in and out, or loading and unloading, etc. Of course, automatic seatbelt retractors contain those components of a seatbelt system that prevent a forward movement of a person secured by the seatbelt when the motor vehicle is subjected to rapid deceleration. A locking device that prevents unwinding of the seatbelt in such cases carries this out. To distinguish from further locking devices which may be provided, this module is described as the main locking means.
Further locking devices of this type can include a so-called vehicle-sensitive and/or webbing-sensitive locking or blocking device. Both blocking devices serve to prevent a forward movement of the person secured by the seatbelt system even during decelerations of the motor vehicle which are lower than the decelerations releasing the main locking means. As these blocking devices come into action before activation of the main locking means, they are frequently also described as pre-locking or pre-blocking devices. The respective pre-blocking device is able to lock the seatbelt system to prevent further unwinding of the seatbelt webbing also via the main locking means.
As the seatbelt frequently secures not only a person but also child seats or other bulky objects transported inside the vehicle, a further pre-locking device is frequently provided in the known automatic seatbelt retractors, in order to lock the automatic seatbelt retractor against further extraction after extraction of a predetermined length of seatbelt webbing from the winding shaft. Although the seatbelt can be retracted again until the child seat and/or the bulky object is firmly secured by the seatbelt, the seatbelt cannot be further extracted. This prevents the object secured in this way from moving during deceleration of the motor vehicle. This pre-locking device is frequently referred to as a child seat locking device.
European Patent 0 625 449 discloses an automatic seatbelt retractor of the type mentioned at the outset with a child seat locking device in which a rotatably mounted securing lever is provided. The securing lever acts at both ends and can be pivoted from a rest position into a locking position according to the predetermined extracted length of the seatbelt by means of an actuating device. The securing lever is biased into the rest position by means of a spring, exceeds its"" dead center position during actuation thereof by the actuating device and is then biased into the locking position again by the spring. The securing lever engages teeth of a wheel non-rotatably connected to the winding shaft, the teeth on the exterior of this wheel being in the form of saw teeth. The saw teeth point in the unwinding direction. The securing lever can therefore pass over the wheel in the take-in direction of the seatbelt webbing as the locking position is released and can finally pivot back into its"" rest position.
This well functioning child seat locking device contains, in addition to the actuating device, two separate components that are small in construction owing to the restricted space in automatic winding devices of this type. This makes assembly, in particular of the springs, difficult and time-consuming. This is a drawback, in particular if assembly is to be carried out using automatic assembly devices.
There is provided in accordance with the present invention an automatic seatbelt retractor of the type mentioned at the outset in which the child seat locking device has fewer components compared to those of the prior art.
Since only a single intermediate element is required for actuation of the securing components by the actuating device, with the solution according to the invention. Not only are the pure material and production costs reduced as the number of components is diminished, but also the assembly costs are reduced, since only a single component has to be assembled in addition to the components already used in the past.
In this connection, it should be pointed out that the intermediate element is able to act on an independent securing component for the child seat locking device. It is also possible for the intermediate element to act on an existing securing component of one of the above-mentioned pre-locking devices, in particular the vehicle-sensitive prelocking or pre-blocking device. The securing component can be a pre-blocking pawl that engages in the teeth of a gear wheel that is non-rotatably connected to the winding shaft.
For a compact construction of the automatic seatbelt retractor according to the invention, the vehicle-sensitive pre-blocking device can comprise a carrier disc on which the intermediate element and optionally the securing component are rotatably or pivotally mounted.
In order to maintain this position, it is in principle sufficient for either the actuating device or the intermediate element to be releasably lockable in the locking position of the pre-locking device or of the child seat locking device, in order to maintain this position. To achieve greater security, however, the actuating device and the intermediate element can also be releasably lockable, independently of one another, in the locking position of the pre-locking device. Catch pins for fixing the actuating device and the intermediate element can be provided on the carrier disc for this purpose.
In order to maintain actuation of the intermediate element as simple as possible, it has proven advantageous if the intermediate element comprises at least one cam portion which is in engagement with the actuating device, and one actuating portion which actuates the securing component triggering the pre-locking of the winding shaft.
To prevent the pre-locking position from being released prematurely, it is preferably also proposed that the intermediate element have a locking portion for the releasable locking of the intermediate element in its"" locking position.
In principle, it would be conceivable for the actuating device to be actuated merely by a movement derived from the winding shaft. It is advantageous, however, if the actuating device is a reduction gear that is in direct rotational connection with the winding shaft.
Furthermore, the actuating device can again have any construction. It is advantageous if the actuating device contains a tumbling disc which is arranged eccentrically on the winding shaft, is rotatably connected thereto and, as a function of the extracted length of the seatbelt webbing, actuates an activation disc which is rotatably mounted on the winding shaft and is in engagement with the intermediate element. The tumbling disc can have external teeth that roll on internal teeth that are stationary relative to the rotating tumbling disc.
For actuating the cam portion of the intermediate element, the activating disc can be provided, on its"" outer circumference, with a corresponding control contour that scans the cam portion.
To enable the activating disc to actuate the intermediate element when the predetermined length of seatbelt webbing is extracted, the activating disc can have an arcuate recess in which engages a driving pin non-rotatably connected to the tumbling disc. Starting with completely retracted seatbelt webbing, initially the winding shaft, and therefore also the tumbling disc, are set into rotation as the seatbelt webbing is extracted. When a first predetermined extracted length is reached, the driving pin of the tumbling disc comes into contact with one edge of the arcuate recess of the activating disc and entrains the activating disc. The cam portion of the intermediate element therefore slides on the control contour of the outer circumference of the activating disc and, after reaching the second predetermined extracted length, actuates the securing component of the pre-locking device.
To avoid premature release of the pre-locking device, the activating disc can also be lockable in the pre-locking position. This catching of the activating disc in the pre-locking position can be achieved by means of a catch lever which is provided at the outer circumference of the activating disc and rests releasably on a catch pin which is stationary in the pre-locking position of the catch lever. This catch pin can in turn be provided on the vehicle-sensitive pre-locking device. To enable the catch lever of the activating disc to be released from the catch pin on release of the pre-locking position, the catch pin can also have a contour that is such that the catch lever is not blocked on the catch pin.
To achieve secure locking, it is also advantageous if the securing component is formed by a pawl which is pivotally mounted and which can be pivoted by the intermediate element into the pre-locking position in which the pawl engages in the saw teeth of external teeth of a wheel non-rotatably connected to the winding shaft, the saw teeth pointing in the unwinding direction.
For reducing the weight of the automatic seatbelt retractor according to the invention and the production costs, it is of further advantage that the intermediate element is produced from a plastic material.